Bicyclooctane derivatives as plasticizers

ABSTRACT

The use of isosorbide esters, isosorbide polyesters, isosorbide ethers, isosorbide carbonates, isosorbide thioethers, isosorbide thioesters, isosorbide amides, isosorbide (thio)urethanes, isosorbide urea, isosorbide phosphates and isosorbide phosphonates as a plasticizer is described. Instead of isosorbide it is also possible for corresponding diols such as isomannide and similar compounds, in which the ring oxygen atoms of the isosorbide have been replaced by carbon or by other heteroatoms, to serve as a base. In particular, this relates to C 3 -C 11  alkanoates of isosorbide, isomannide and the like. In particular, the compounds are used as a plasticizer inpoly(vinylchloride), optionally in conjunction with usual plasticizers such as dioctyl phthalates.

The invention relates to the use of bicyclo[3.3.0]octane derivatives asplasticisers or solvents for polymers. including thermoplastics.

Plasticisers are indispensable components for thermoplastic materialssuch as poly(vinyl chloride), and other polymer systems. The mostcommonly used plasticisers are diesters of dicarboxylic acids, amongwhich the phthalic acid diesters are frontrunners in the plasticisermarket with 89%, about half of which is made up of the isomericdiisooctyl esters. Whilst the existing plasticisers are generallysatisfactory, there is a need for the range of plasticisers to beextended. Moreover. the existing plasticisers are virtually withoutexception based on petroleum products, whereas it is desirable for theseto be replaced. as far as possible, by renewable raw materials. From anenvironmental and health point of view it is likewise desirable fordialkyl phthalates to be replaced.

Polyesters based on isosorbide and dicarboxylic acids (adipic acid,suberic acid, sebacic acid and dodecanedioic acid) having molecularweights above 10,000 have been suggested by Braun and Bergmann (Angew.Makromol. Chem. 199 (1992), 191-205) as plasticisers for PVC.JP-A-8-173788 describes the use of fatty acid diesters of sorbitans andisosorbide as an emulsifier. JP-A-59-175408 discloses the cosmetic useof esters of isosorbide with fatty acids having more than 8 carbonatoms. WO 96/33689 describes the use of a plasticising solvent,including dimethyl isosorbide, in film-forming water-in-oil emulsionsfor use in cosmetics.

We have now found that esters and ethers based on isosorbide andanalogous derivatives having a low molecular weight have excellentcharacteristics as plasticisers and solvents for polymer materials. Thederivatives are defined in the appended claims. The central unit ofthese derivatives is a bicyclo[3.3.0]octane-4,8-diyl system, whosecarbon atoms in the 2- and 6- position may be replaced by a heteroatom,such as sulphur and in particular oxygen. The attachment of side chainsin the 4- and 8- positions can take the form of an ether, ester,(thio)carbonate. thioether, thioester, amide, (thio)-urethane, urea,phosphate or phosphonate. Esters are preferred, but carbonates,urethanes and especially ethers can also advantageously be used.Phosphates and phosphonates are preferred when in addition to theplasticising effect a flame retardant effect is desired.

The side chains thus attached are preferably medium-length alkyl groups.Medium length means at least 3 carbon atoms. preferably at least 4carbon atoms, especially (for ethers) at least 6 carbon atoms, up to 10or even 12 carbon atoms. Where reference is made to alkyl, alkenyl etc.,these terms include both linear and branched groups. depending on theparticular use. branched groups, e.g. isobutyl, isooctyl, isononyl,2-ethylhexyl and the corresponding acyl groups, or unbranched groups maybe preferred. Examples of suitable alkanoyl groups include butanoyl,hexanoyl, 2-ethyl-hexanoyl, octanoyl, decanoyl, and unsaturated groupssuch as benz(o)yl and undecenoyl. Mixtures of alkyl groups are suitableas well, their average chain length is preferably C₄-C₁₂.

It is also possible for oligoester side groups of a diacid and a diol,for example succinic acid, which may or may not be substituted. andisosorbide, or of a hydroxy acid such as hydroxystearic acid orcaprolactone, to be attached, with an alkyl or alkanoyl group as theterminal group. The chain length of such oligomeric side groups is 1-20,preferably 1-10, most preferably 1-5 repeating units on either side ofthe central unit, with molecular weights preferably between about 600and 2000.

The derivatives according to the invention can be prepared in a mannerknown per se. Derivatives where X represents an oxygen atom in formula 1can be prepared starting from isosorbide or the isomericdianhydrohexitols such as isomannide and isoidide. The dianhydrohexitolscan in turn be obtained from the corresponding monosaccharides (glucose,mannose) and di- and polysaccharides (sucrose, maltose, lactose, starch,cellulose, galactomannans and the like). Derivatives where one of theatoms X is a nitrogen or a sulphur atom can be prepared in a similarmanner from a suitable amino or thio sugar. Derivatives where both atomsX are sulphur atoms can be prepared starting from1,4-dithiapentalen-3-one which, by reduction and addition, can beconverted into a 4,8-disubstituted 2,6-dithiabicyclooctane. Derivativeswhere one of the groups Y contains a nitrogen or sulphur atom can beobtained from the corresponding 2-amino- or 2-thio sugars, such as ahydrolysis product of chitin. The side chains can be introduced byesterification (eg. using a reactive carboxylic acid derivative),etherification, isocyanate addition, and the like. Polyester side groupscan be introduced in a manner known per se, by polycondensation of thesuitable dicarboxylic acids and diols or hydroxy acids.

The derivatives according to the invention can be worked into polymermaterials in a manner known per se. In general, the polymer and theplasticiser can be mixed in a ratio of between 100:1 and 1:9. The ratiois preferably from 10:1 to 10:8. In addition to the plasticisers orplasticising solvents according to the invention, other customarycomponents are used such as stabilisers, flow improvers, pigments,antioxidants, UV absorbers, flame retardants. fillers, oligomeric orpolymeric resins or varnishes, reactive monomers, activators, starters,desiccants, lubricants, waxes. solvents, biocides and the like. This mayinvolve, for example, organic compounds of calcium. magnesium, zinc orbarium, β-diketo compounds, β-ketoesters, β-aminocrotonates, uracilderivatives, dihydropyridine derivatives, sterically hindered phenols,sterically hindered amines, phosphites, polyols and hydrotalcites. It isalso possible, advantageously, for the plasticisers according to theinvention to be combined with known plasticisers such as dialkylphthalates, dialkyl adipates, dialkyl azelates and dialkyl sebacates,alkylbenzyl phthalates, trialkyl trimellitates, triaryl phosphates,citric acid esters, alkyl benzoates and polyesters based on adipic acidor azelaic acid, and thus for an optimal combination to be achieved interms of compatibility, renewability, degradability, and plasticisingproperties.

The derivatives according to the invention can be used for plasticisingand/or solubilising any polymer systems, including thermoplasts (PVCetc.), rubbers, inks, coatings, adhesives, sealants. foams andthermosetting resins.

Examples of the use as plasticiser are given below. The plasticisers areused in a manner known for plasticisers and plasticising solvents, asdescribed e.g. in: I. Skeist (ed.), Handbook of Adhesives. 3rd ed., VanNostrand Reinhold, NY (1990), and H. F. Mark, Encyclopedia of polymerScience and Engineering, 2nd ed., NY (1985). Sealants: The derivativesof the invention can be used as a plasticiser in sealants and caulks,for example in a one or two-component polysulphide sealant or inacrylates or polysiloxanes or natural or synthetic rubbers. In additionto the plasticisers, other components may used in a sealant: epoxidisedunsaturated oil (soy, fish, linseed oil), inorganic pigments,desiccants, fillers, and activators such as silica, calcium carbonate,titanium dioxide, lime, zeolites, and adhesion aids, such asorganosilicon compounds, and aqueous or organic solvents).

50% liquid polysulphide polymer 30-70% 4% epoxidised soya oil 0-10% 2%silica 0-5% 22% titanium dioxide general: inorganic pigment 1-25% 5%calcium carbonate in general: 2% lime fillers, activators etc. 1-15% 2%zeotite 4% calcium peroxide (curing agent) 1-10% 2% plasticiseraccording to the 1-20% invention 1% 3-aminopropyltriethoxysilane0.1-2.5% Remainder: toluene

Printing inks: The derivatives of the invention can be used asplasticiser or solvent in printing ink formulations for application inletterpress (relief), gravure (intaglio), offset lithography(planographic), screen (stencil), electrostatic (reprography) and jet(ink spray) printing. Suitable polymer systems for printing inks includeacrylates, rosins, polyamides, polyesters, hydrocarbon resins, alkydresins, nitrocellulose, cellulose acetates, etc.

Example of flexographic ink formulation (phr = parts per hundred): 35phr titanium dioxide 5-45% 12 phr polyamide resin 5-25% 2 phrnitrocellulose 1-10% 3 phr plasticiser of the invention 2-20% 5 phrisopropyl acetate general: 43 phr isopropanol 20-60% solvent Example ofgravure ink formulation: 10 phr organic pigment or dye 1-15% 5 phrinorganic extender 1-20% 5 phr plasticiser of the invention 2-20% 12 phracrylic varnish general: 38 phr nitrocellulose varnish varnish 20-80% 5phr wax compound 2-8% 15 phr ethanol general: 10 phr isopropyl acetatesolvent 5-35% Example of gravure ink formulation: 12 phr organic pigment1-15% 10 phr titanium dioxide general: inorganic pigment 1-20% 4 phrplasticiser of the invention 2-20% 15 phr maleic varnish general: 40 phrnitrocellulose varnish varnish 20-80% 4 phr polyethylene wax 2-8% 10 phrethanol general: 5 phr isopropyl acetate solvent 5-35% Example ofscreen-printing ink formulation 3 phr organic pigment 2-20% 25 phr talc5-40% 36 phr acrylated monomer general: 26 phr 1,6-hexanediol diacrylatereactive monomer 40-75% 10 benzophenone general: initiator 1-15% 3 phrplasticiser of the invention 1-20%

Adhesives and coatings: The derivatives of the invention can be used asplasticisers in adhesives. Their function is to improve the flexibility,wetting properties and water resistance. The derivatives of theinvention are applied as plasticiser for adhesives and sealants of thefollowing classes: natural rubber; synthetic rubber, e.g. butyl,nitrile, neoprene, isoprene, styrene-butadiene rubber and copolymersthereof; carboxylated rubber and carboxyl functional polymers, e.g. andacrylic acid polymers and copolymers; phenolic and amino resin (e.g.urea, melamine); polysulphide resins and adhesives; epoxy resins andadhesives; polyurethanes and isocyanate-functional adhesives; polyvinylalcohol and polyvinyl acetate and acetal adhesives; acrylate,cyanoacrylate and acrylic acid adhesives and their copolymers; polyesterand polyamide; silicone adhesives The types of adhesives include:reactive one-and two component adhesives; hot-melt adhesives;delayed-tack adhesives; solution adhesives; in particularpressure-sensitive adhesives.

Example: two-component vinyl flooring adhesive

general: Part A: 212.5 phr hydrocarbon resin resin 37.5 phr mineralspirit solvent 12.5 phr plasticiser of the invention plasticiser 12.5phr methanol solvent 7.5 phr nonionic surfactant surfactant 50 phr clayfiller Part B: 100 phr high-solids SBR latex latex/polymer 0.5 phrphosphate stabiliser 0.5 phr potassium hydroxide 0.1 phr defoamer Waterto total solids content 60% water

Rubbers and thermoplastic elastomers: The plasticisers of the inventioncan be used as plasticisers in cured or non-cured natural and syntheticrubbers, and in thermoplastic elastomers. These include all commonrubbers, in particular acrylonitrile butadiene rubber (NBR), chloroprenerubber (CR), styrene butadiene rubber (SBR), polybutadiene (BR), 1 to100 parts, in particular, 5-30 parts. The derivatives are used fordecreasing the glass temperature of the rubber and for increasingtensile strength and strength on rupture. Thermosets: The plasticisersof the invention can be used as plasticisers in thermosetting resins(e.g. polyesters, amino resins) in order to improve the toughness andelongation. Foams: The derivatives of the invention can also be used asplasticisers in polymeric foams, in particular polyurethane, polyetherand latex (natural or synthetic rubber) foams. They can be used toincrease compression strength of the foam, refine the cell structure,improve its insulation resistance and increase its tenacity or otherchemical, physical or mechanical properties.

EXAMPLE 1 Preparation of Isosorbide Dioctanoate (ISDO)

In a 500 ml flask, provided with a Dean-Stark apparatus, a solution of25 g (0.171 mol) of isosorbide, 54 g of n-octanoic acid (0.375 mol) and1.0 g of p-toluenesulphonic acid was boiled for 2 hours in 130 ml ofxylene. After cooling, 250 ml of diethyl ether were added and thesolution was washed with 1225 ml of 0.1 M NaOH and then with water untilthe water phase remained neutral. The organic phase was evaporated,whereupon 65 g (95%) of product were isolated.

¹³C-NMR (δ, ppm, CDCl₃): 13.9 (—CH₃),22.5+24.7+28.8+31.1+31.5+33.8+70.2+73.3 (—CH₂—), 73.6+77.7 (CHO),80.6+85.8 (CHOR), 172.7 (OCO).

EXAMPLES 2-5 Preparation of Isosorbide Dibutanoate (ISDB) IsosorbideDihexanoate (ISDH) and Isosorbide bis(2-ethylhexanoate) (ISDEH) andIsomannide Dioctanoate (IMDO)

Using the method of Example 1, starting from the appropriate alkanoicacids and dianhydrohexitols, the title compounds were obtained:

ISB: Yield 87%, ¹³C-NMR: 13.3(—CH₃), 18.1+35.5+70.2+73.0 (—CH₂—),73.6+77.6 (CHO), 80.5+85.7 (CHOR), 172.1 (OCO).

ISH: Yield 86%, ¹³C-NMR: 13.5 (—CH₃), 22.0+24.2+31.0+33.7+70.1+73.0(—CH₂—), 73.6+77.6 (CHO), 80.5+85.7 (CHOR), 172.1 (OCO).

ISEH: Yield 89%, ¹³C-NMR: 11.5+13.6 (—CH₃),22.4+25.1+29.1+31.4+70.4+73.0 (—CH₂—), 46.7 (—CH—), 73.4+77.5 (CHO),80.5+85.9 (CHOR), 174.8 (OCO).

IMO: Yield 91%, ¹³C-NMR: 14.0 (—CH₃), 22.5+24.8+28.8+28.9+31.6+33.9+70.4(—CH₂—), 73.5 (CHO), 80.3 (CHOR), 173.2 (OCO).

EXAMPLE 6 Preparation of Plasticised PVC

A two-roll calender was used to make a film from the PVC compound at142° C., followed by determination of the glass transition temperature(Tg) by means of DMTA (Dynamic-mechanical thermal analysis).

100 parts of PVC

50 parts of plasticiser according to Example 1

1.0 part of hydrotalcite

0.3 part of zinc laurate

0.3 part of calcium stearate

The Tg was 0° C.; that of non-plasticised PVC that otherwise had thesame composition was 80° C., and that of PVC plasticised with the sameamount of dioctyl phthalate (DOP) was −13° C. The modulus of elasticityat −20° C. was 10⁹ Pa, at 40° C. 10⁷ Pa and at 100° C. 3.10⁶ Pa, valuescomparable to those of PVC plasticised with DOP.

EXAMPLE 7 Preparation of Plasticised PVC

A film obtained according to Example 6 on the basis of the followingcompounds:

100 parts of PVC

30-50 parts of plasticiser according to Examples 1-5

1.0 part of hydrotalcite

0.3 part of zinc laurate

0.3 part of calcium stearate was made into small rods whose glasstransition temperature was determined by means of DMTA and whose modulusof elasticity and breaking behaviour were determined on a tensiletesting machine. The results—as yet not optimised—were compared withthose of dibutyl phthalate (DBP) and dioctyl phthalate (DOP) and areshown in Table 1:

TABLE 1 breaking breaking amount Tg (E″max) E (Mpa) at tensionelongation plasticiser (phr) (° C.) T = 17.6° C. (MPa) (%) ISDB 30 25670 28 165 ISDH 30 21 310 26 142 ISDEH 30 26 n.d. n.d. n.d. ISDO 30 18600 24 135 IDMO 30 27 390 29 207 DBP 30 14 110 18 159 DOP 30 23 240 17130 ISDB 50 2 12 18 193 ISDH 50 −7 14 10 149 ISDEH 50 −5 11 11 234 ISDO50 −9 15 18 228 IMDO 50 −20 26 15 152 DBP 50 −16 7 13 237 DOP 50 −13 2114 205 none — 85 n.d. n.d. n.d. n.d. = not detetmined

EXAMPLE 8 Preparation of Plasticised NBR

To a commercial acrylonitrile-butadiene rubber (NBR) compound containingcarbon black, stabilisers. crosslinkers and further conventionaladditives was added 20 phr of plasticiser according to the invention(isosorbide bis(2-ethylhexanoate ISDEH) 40° C. After extensive mixing,the mixture was vulcanised at 170° C. in a die having dimensions of180×120×1 mm. The vulcanisation time was 7 minutes. The vulcanisedmaterial was conditioned at 50% relative humidity for two days andpunched in accordance with ISO 37. The mechanical properties weredetermined using a tensile strength tester (Zwick Z010). The E-moduluswas determined at 1 mm/min, the other properties at 500 mm/min, inaccordance with ISO 12184. Table 2 shows the results, with standarddeviations in parentheses.

TABLE 2 without 20 phr 20 phr Property plasticiser DOP ISDEH unitE-modulus  7 (1)  2 (0)  3 (0) N/mm² Stress at 100% strain  4.2 (0.1) 1.5 (0.1)  1.6 (0.2) N/mm² Stress at 300% strain 15.1 (0.5)  7.1 (0.3) 7.7 (0.4) N/mm² Stress at break 15.4 (1.8) 13.0 (1.4) 13.0 (0.8) N/mm²Strain at break 354 (49) 499 (38) 469 (26) %

What is claimed is:
 1. A process for plasticizing or dissolving apolymer, comprising contacting a polymer with a bicyclo[3.3.0]octanederivative having formula 1:

wherein R represents C₅-C₁₀ alkyl or alkenyl.
 2. A process according toclaim 1, wherein 1-900 parts by weight of the bicyclooctane derivativeare used per 100 parts of synthetic polymer to be plasticised.
 3. Aprocess according to claim 1, wherein a dialkyl phthalate, adipate orsebacate, or trialkyl trimellitate, phosphate, citrate and/or apolyester are also used.
 4. A process according to claim 1, wherein saidpolymer is PVC.
 5. A process according to claim 1, wherein said polymeris a rubber.
 6. A process according to claim 1, for plasticisingcoatings or adhesives.
 7. A process according to claim 1, forplasticising an ink.
 8. A process according to claim 1, for plasticisinga sealant.
 9. A process according to claim 1, for plasticising a polymerfoam.
 10. Mixture of plasticisers which comprises 20-90 wt % of abicyclo[3.3.0]octane derivative as defined in claim 1 and 10-80 wt % ofat least one of a dialkyl phthalate, adipate, sebacate, or a trialkyltrimellitate, phosphate, citrate, an alkyl benzoate or a polyester. 11.A plasticized polymer comprising 1-900 parts by weight of abicyclooctane derivative according to claim 1 per 100 parts of asynthetic polymer.